Packers are used in wellbores to isolate specific wellbore regions. A packer is delivered downhole on a conveyance and expanded against the surrounding wellbore wall to isolate a region of the wellbore. Two or more packers can be used to isolate one or more regions in a variety of well related applications, including production applications, service applications and testing applications.
In some applications, straddle packers are used to isolate specific regions of the wellbore to allow collection of fluid samples. However, straddle packers employ a dual packer configuration in which fluids are collected between two separate packers. The straddle packer configuration is susceptible to mechanical stresses which limit the expansion ratio and the drawdown pressure differential that can be employed. Other multiple packer techniques can be expensive and present additional difficulties in collecting samples and managing fluid flow in the wellbore environment.